Pathological relevance of epithelial and mesenchymal phenotype plasticity

Expression of epithelial–mesenchymal transition-associated proteins and proliferating cell nuclear antigen in dihydropyridine-induced gingival overgrowth fibroblasts: A preliminary study

Background/purpose

The clinical features of dihydropyridine-induced gingival overgrowth (DIGO), including extracellular matrix accumulation and cell hyperplasia, are regulated by inflammatory factors (e.g., Interleukin-1β [IL-1β]) in combination with calcium channel blockers (e.g., nifedipine [Nif]). We speculated that IL-1β and Nif (IL-1β/Nif) may be the main factor modulating the proliferative potential and turnover of fibroblasts in DIGO.

Materials and methods

We cultured four DIGO fibroblast strains and analysed the possible effects of IL-1β/Nif treatments on epithelial-mesenchymal transition (EMT)-associated proteins. We developed short hairpin ribonucleic acids (shRNAs) and used them to explore the role of IL-1β/Nif in regulating proliferating cell nuclear antigen (PCNA) levels in DIGO tissues.

Results

Our results revealed that compared with control cells, DIGO cells stimulated with IL-1β/Nif had higher levels of the EMT-associated proteins Snail, Slug, and Twist. Moreover, both drugs enhanced androgen receptor (AR), Slug, and PCNA expression.

Conclusion

Taken together, our data indicate that proinflammatory cytokines in combination with calcium channel blockers can regulate the expression of EMT-associated proteins and increase the proliferative potential of DIGO fibroblasts.

Senescence-Associated Pro-inflammatory Cytokines and Tumor Cell Plasticity

The well-recognized cell phenotypic heterogeneity in tumors is a great challenge for cancer treatment. Dynamic interconversion and movement within a spectrum of different cell phenotypes (cellular plasticity) with the acquisition of specific cell functions is a fascinating biological puzzle, that represent an additional difficulty for cancer treatment and novel therapies development. The understanding of the molecular mechanisms responsible for moving or stabilizing tumor cells within this spectrum of variable states constitutes a valuable tool to overcome these challenges. In particular, cell transitions between epithelial and mesenchymal phenotypes (EMT-MET) and de-and trans-differentiation processes are relevant, since it has been shown that they confer invasiveness, drug resistance, and metastatic ability, due to the simultaneous acquisition of stem-like cell properties. Multiple drivers participate in these cell conversions events. In particular, cellular senescence and senescence-associated soluble factors have been shown to unveil stem-like cell properties and cell plasticity. By modulating gradually the composition of their secretome and the time of exposure, senescent cells may have differential effect not only on tumor cells but also on surrounding cells. Intriguingly, tumor cells that scape from senescence acquire stem-like cell properties and aggressiveness. The reinforcement of senescence and inflammation by soluble factors and the participation of immune cells may provide a dynamic milieu having varied effects on cell transitions, reprogramming, plasticity, stemness and therefore heterogeneity. This will confer different epithelial/mesenchymal traits (hybrid phenotype) and stem-like cell properties, combinations of which, in a particular cell context, could be responsible for different cellular functions during cancer progression (survival, migration, invasion, colonization or proliferation). Additionally, cooperative behavior between cell subpopulations with different phenotypes/stemness functions could also modulate their cellular plasticity. Here, we will discuss the role of senescence and senescence-associated pro-inflammatory cytokines on the induction of cellular plasticity, their effect role in establishing particular states within this spectrum of cell phenotypes and how this is accompanied by stem-like cell properties that, as the epithelial transitions, may also have a continuum of characteristics providing tumor cells with functional adaptability specifically useful in the different stages of carcinogenesis.

Gastric Pathology Image Classification Using Stepwise Fine-Tuning for Deep Neural Networks

Deep learning using convolutional neural networks (CNNs) is a distinguished tool for many image classification tasks. Due to its outstanding robustness and generalization, it is also expected to play a key role to facilitate advanced computer-aided diagnosis (CAD) for pathology images. However, the shortage of well-annotated pathology image data for training deep neural networks has become a major issue at present because of the high-cost annotation upon pathologist's professional observation. Faced with this problem, transfer learning techniques are generally used to reinforcing the capacity of deep neural networks. In order to further boost the performance of the state-of-the-art deep neural networks and alleviate insufficiency of well-annotated data, this paper presents a novel stepwise fine-tuning-based deep learning scheme for gastric pathology image classification and establishes a new type of target-correlative intermediate datasets. Our proposed scheme is deemed capable of making the deep neural network imitating the pathologist's perception manner and of acquiring pathology-related knowledge in advance, but with very limited extra cost in data annotation. The experiments are conducted with both well-annotated gastric pathology data and the proposed target-correlative intermediate data on several state-of-the-art deep neural networks. The results congruously demonstrate the feasibility and superiority of our proposed scheme for boosting the classification performance.

EMT influences the expression of CK19 in pleural effusion-derived lung cancer cells and their invasion and metastasis

Lung cancer is the most common cancer after breast and colon cancer, with high rates of mortality, worldwide. There are two main types of lung cancer, small cell lung carcinoma (SCLC), which accounts for approximately 20% of all lung cancer cases and non-SCLC, which accounts for almost 80% of lung cancer cases. Although lung cancer is one of the most aggressive types of cancer, progress in achieving better clinical outcomes has been gradual. Even though a number of markers have been suggested for the diagnosis of lung cancer and monitoring of disease progression, there is no clear way of assessing the invasion, epithelial-mesenchymal transition (EMT) and metastasizing capability of the primary tumor cells. We investigated the incidence of cytokeratin 19 (CK19)-negative expressers in different types of lung cancer from 111 lung cancer patients, their serum and pleural effusion CYFRA21-1 levels and whether induction of EMT in the primary focus cells influences the expression of CK19. In addition, we examined whether CK19-negative lung cancers were more invasive and metastatic. We also examined the propensity of primary focus cells to undergo EMT in the presence of transforming growth factor-β1 (TGF-β1). The results obtained suggested that the invasion and metastasis of lung tumor cells can be assessed by having a complete picture of serum CYFRA21-1 together with the CK19 expression status of primary focus cells and pleural effusion. This assessment may be further improved by examining the propensity of the isolated primary focus cells to undergo TGF-β1 induced EMT in cell culture.

Suitable Materials for Soft Tissue Reconstruction: In Vitro Studies of Cell – Triblock Copolymer Interactions

Keratinocytes and fibroblasts have been grown onto a series of triblock copolymers based on 1,5-dioxepan-2-one (DXO) and L-lactide (LLA). The molar ratio of DXO and LLA were varied in the copolymers. This resulted in different degrees of hydrophilicity, which in turn influenced the cell growth. On these surfaces, the morphological appearance of the cells with their cell movements and growth were investigated by means of scanning electron microscopy, time-lapse videomicroscopy and immunohistochemistry. All results clearly showed that the keratinocytes and fibroblasts adhered best to the most hydrophilic copolymers. A majority of the keratinocytes seeded on the most hydrophilic copolymer also presented a polarized morphology indicating a migration tendency. The cell growth onto these materials are interesting since a possible application for these unique materials is as polymeric membranes for guided cutaneous and/or periodontal tissue generation.

Role of transforming growth factor-beta1 in cyclosporine-induced epithelial-to-mesenchymal transition in gingival epithelium

BACKGROUND

It has been proposed that cyclosporin A (CsA) may induce epithelial-to-mesenchymal transition (EMT) in gingiva. The aims of the present study are to confirm the notion that EMT occurs in human gingival epithelial (hGE) cells after CsA treatment and to investigate the role of transforming growth factor beta1 (TGF-β1) on this CsA-induced EMT.

METHODS

The effects of CsA, with and without TGF-β1 inhibitor, on the morphologic changes of primary culture of hGE cells were examined in vitro. The changes of protein and messenger RNA (mRNA) expressions of two EMT markers (E-cadherin and alpha-smooth muscle actin) in the hGE cells after CsA treatment with and without TGF-β1 inhibitor were evaluated with immunocytochemistry and real-time polymerase chain reaction.

RESULTS

The epithelial cells became spindle-like, elongated, and disassociated from neighboring cells and lost their original cobblestone monolayer pattern when CsA was added. However, the epithelial cells stayed in their original cobblestone morphology with treatment of TGF-β1 inhibitor on top of the CsA treatment. When CsA was given, the protein and mRNA expressions of E-cadherin and α-SMA were significantly altered, and these alterations were significantly reversed with pretreatment of TGF-β1 inhibitor.

CONCLUSIONS

CsA could induce Type 2 EMT in gingiva by changing the morphology of epithelial cells and altering the EMT markers/effectors. The CsA-induced gingival EMT is dependent or at least partially dependent on TGF-β1.

Signal pathways associated with epithelial-mesenchymal transition in metastasis of primary hepatocelluar carcinoma

Epithelial-mesenchymal transition (EMT) is a phenomenon in which epithelial cells lose their epithelial characters and acquire mesenchymal characters. EMT can be seen in embryogenesis, organ fibrosis and tumor metastasis. EMT can be observed in metastasis of primary hepatocelluar carcinoma (HCC). This review focuses on several signal pathways associated with EMT, such as TGF-β, Wnt (wingless-type)/β-catenin, and Hedgehog signal pathways. Other factors involved in EMTs, such as NF-κB, Notch, miRNA, CHD1L, ARHGEF9, HBX, and extracellular matrix are also discussed in this article. A better understanding of the mechanism of EMT can help us find new targets for HCC treatment.

Collective and single cell behavior in epithelial contact inhibition

Control of cell proliferation is a fundamental aspect of tissue physiology central to morphogenesis, wound healing, and cancer. Although many of the molecular genetic factors are now known, the system level regulation of growth is still poorly understood. A simple form of inhibition of cell proliferation is encountered in vitro in normally differentiating epithelial cell cultures and is known as "contact inhibition." The study presented here provides a quantitative characterization of contact inhibition dynamics on tissue-wide and single cell levels. Using long-term tracking of cultured Madin-Darby canine kidney cells we demonstrate that inhibition of cell division in a confluent monolayer follows inhibition of cell motility and sets in when mechanical constraint on local expansion causes divisions to reduce cell area. We quantify cell motility and cell cycle statistics in the low density confluent regime and their change across the transition to epithelial morphology which occurs with increasing cell density. We then study the dynamics of cell area distribution arising through reductive division, determine the average mitotic rate as a function of cell size, and demonstrate that complete arrest of mitosis occurs when cell area falls below a critical value. We also present a simple computational model of growth mechanics which captures all aspects of the observed behavior. Our measurements and analysis show that contact inhibition is a consequence of mechanical interaction and constraint rather than interfacial contact alone, and define quantitative phenotypes that can guide future studies of molecular mechanisms underlying contact inhibition.

Direct contribution of epithelium to organ fibrosis: epithelial-mesenchymal transition

Fibrosis of epithelial parenchymal organs and end-stage organ failure represent the final common pathway of many chronic diseases and are a major determinant of morbidity and mortality worldwide. Fibrosis is a complex response initiated to protect the host from an injurious event; nevertheless, it leads to serious organ damage when it becomes independent from the initiating stimulus. It involves massive deposition of matrix by an expanded pool of fibrogenic cells, disruption of the normal tissue architecture, and parenchymal destruction. Fibroblasts, the effector cells of matrix production, when engaged in fibrogenesis, display the highly activated phenotype characteristic of myofibroblasts. These cells are present in a large number in sites with ongoing inflammation, reparative reaction, and fibrosis, but their origin has not yet been definitely elucidated. Although proliferation of preexisting stromal fibroblasts and, probably, recruitment of bone marrow-derived fibrogenic cells may account for a portion of them, emerging evidence seems to indicate that an important number of matrix-producing fibroblasts/myofibroblasts arises through a mechanism of epithelial-mesenchymal transition. Through this process, epithelial cells would lose intercellular cohesion and would translocate from the epithelial compartment into the interstitium where, gaining a full mesenchymal phenotype, they could participate in the synthesis of the fibrotic matrix. Epithelial-mesenchymal transition is induced by the integrated actions of many stimuli including transforming growth factor-beta and matrix-generated signals that are also known to be implicated in inflammation, repair responses, and fibrosis. The consequences of epithelial-mesenchymal transition in chronic fibrosing diseases could be two-fold as follows: on one hand, by supplementing new mesenchymal cells, it might feed the expanding pool of interstitial fibroblasts/myofibroblasts responsible for the matrix accumulation; on the other hand, it could cause loss of epithelial cells, thus, contributing to the parenchyma destruction seen in advanced fibrosis. Markers of epithelium undergoing epithelial-mesenchymal transition include loss of E-cadherin and cytokeratin; de novo expression of fibroblast-specific protein 1/S100A4, vimentin, and alpha-smooth muscle actin; basement membrane component loss; and production of interstitial-type matrix molecules such as fibronectin and type I/III collagen. Evidence of epithelial-mesenchymal transition has been reported in the kidney, lung, liver, eye, and serosal membranes suggesting that epithelial-mesenchymal transition could be involved in the pathogenesis of fibrotic disorders in these organs. Thus, because of its fibrogenic potential, the detection of epithelial-mesenchymal transition in biopsy specimens could be useful diagnostically and represent a new biomarker of progression in chronic fibrosing diseases.

Hedgehog signaling regulates epithelial-mesenchymal transition during biliary fibrosis in rodents and humans

Epithelial-mesenchymal transitions (EMTs) play an important role in tissue construction during embryogenesis, and evidence suggests that this process may also help to remodel some adult tissues after injury. Activation of the hedgehog (Hh) signaling pathway regulates EMT during development. This pathway is also induced by chronic biliary injury, a condition in which EMT has been suggested to have a role. We evaluated the hypothesis that Hh signaling promotes EMT in adult bile ductular cells (cholangiocytes). In liver sections from patients with chronic biliary injury and in primary cholangiocytes isolated from rats that had undergone bile duct ligation (BDL), an experimental model of biliary fibrosis, EMT was localized to cholangiocytes with Hh pathway activity. Relief of ductal obstruction in BDL rats reduced Hh pathway activity, EMT, and biliary fibrosis. In mouse cholangiocytes, coculture with myofibroblastic hepatic stellate cells, a source of soluble Hh ligands, promoted EMT and cell migration. Addition of Hh-neutralizing antibodies to cocultures blocked these effects. Finally, we found that EMT responses to BDL were enhanced in patched-deficient mice, which display excessive activation of the Hh pathway. Together, these data suggest that activation of Hh signaling promotes EMT and contributes to the evolution of biliary fibrosis during chronic cholestasis.

The role of epithelial-mesenchymal transition in cancer pathology

Invasion, the hallmark of malignancy, consists in the translocation of tumour cells from the initial neoplastic focus into neighbouring host tissues, and also allows tumour cells to penetrate vessel endothelium and enter the circulation to form distant metastasis. A histological pattern found at the periphery of carcinomas is the presence of individual malignant cells detached from the tumour mass and staying independently within the interstitial matrix of the stroma. While they are readily identified by the pathologist as invading malignant cells, their relationship with the compact-appearing portions of the tumour as well as the mechanism underlying the development of this pattern are not immediately evident at histological level. There is growing evidence suggesting that this change in tumour tissue architecture takes place through a peculiar phenotype modulation known as epithelial-mesenchymal transition (EMT). The essential features of EMT are the disruption of intercellular contacts and the enhancement of cell motility, thereby leading to the release of cells from the parent epithelial tissue. The resulting mesenchymal-like phenotype is suitable for migration and, thus, for tumour invasion and dissemination, allowing metastatic progression to proceed. Although the molecular bases of EMT have not been completely elucidated, several interconnected transduction pathways and a number of signalling molecules potentially involved have been identified. These include growth factors, receptor tyrosine kinases, Ras and other small GTPases, Src, beta-catenin and integrins. Most of these pathways converge on the down-regulation of the epithelial molecule E-cadherin, an event critical in tumour invasion and a 'master' programmer of EMT. E-cadherin gene is somatically inactivated in many diffuse-type cancers such as lobular carcinoma of the breast and diffuse gastric carcinoma, in which neoplastic cells through the entire tumour mass have lost many of their epithelial characteristics and exhibit a highly invasive, EMT-derived histological pattern. E-cadherin down-modulation is also seen in solid, non-diffuse-type cancers at the tumour-stroma boundary where singly invading, EMT-derived tumour cells are seen in histological sections. In this latter scenario, E-cadherin loss and EMT could be transient, reversible processes possibly regulated by the tumour microenvironment and, as a matter of fact, neoplastic cells that have undergone EMT during invasion seem to regain E-cadherin expression and their epithelial, cohesive characteristics at the secondary foci. Since the molecules involved in EMT represent potential targets for pharmacological agents, these findings open new avenues for the control of metastatic spread in the treatment of malignancies.

Overexpression of Cripto and its prognostic significance in breast cancer: a study with long-term survival

INTRODUCTION

Cripto is a founding member of the EGF-CFC family, and plays an important role in tumourigenesis, tumour cell proliferation and migration. We aimed to determine the significance of Cripto expression on the survival of patients with breast cancer.

METHODS

Immunohistochemical detection of Cripto was performed by using mAb C13 on 120 formalin-fixed paraffin-embedded breast tumour specimens in tissue microarrays. This cohort comprises a series of 120 patients with primary operable breast cancer diagnosed between 1989 and 1995, retrieved from the Concord Repatriation General Hospital breast carcinoma database.

RESULTS

Using a cutoff value of 80%, Cripto overexpressed in 57 of the 120 (47.5%) patients. We found significant associations between overexpression of Cripto and the Nottingham Prognostic Index (NPI, p<0.01), histological grade (p<0.01), pathological tumour type (p=0.04), PR (p=0.02) as well as Ki-67 (p=0.02). Univariate analysis reveals that there is a significant correlation between overexpression of Cripto and survival (p=0.0003). Cox regression analysis indicates that the overexpression of Cripto is an independent prognostic factor in breast cancer (HR 2.79, 95%CI 1.20-6.50).

CONCLUSION

The unique epitope recognized by mAb C13 is overexpressed on breast tumour tissues. In this series of invasive breast cancers, overexpression of Cripto was more often found in high grade and poor prognosis tumours compared to low grade and good prognosis breast cancers. Moreover, overexpression of Cripto was significantly associated with decreased patient survival.

Epithelial-mesenchymal transformation during craniofacial development

Epithelial to mesenchymal phenotype transition is a common phenomenon during embryonic development, wound healing, and tumor metastasis. This transition involves cellular changes in cytoskeleton architecture and protein expression. Specifically, this highly regulated biological event plays several important roles during craniofacial development. This review focuses on the regulation of epithelial-mesenchymal transformation (EMT) during neural crest cell migration, and fusion of the secondary palate and the upper lip.

Sarcomatoid carcinomas of the lung—are these histogenetically heterogeneous tumors?

Sarcomatoid carcinomas (SC) of the lung are a heterogeneous group of nonsmall cell lung carcinomas (NSCLC) containing a sarcoma or sarcoma-like component. SC may represent an epithelial neoplasm undergoing divergent tissue differentiation originating from a single clone. Epithelial-mesenchymal transition (EMT) best describes the origin of the spindle and giant cells. We aimed to define chromosomal aberrations within the subgroups of SC and if EMT does play a role in SC. Twenty-two SC were investigated by chromosomal comparative genomic hybridization (CGH). Immunohistochemical staining was performed with antibodies for E-cadherin, Vimentin, c-Fos, c-Jun, Snail, TGFbeta1, Notch1, beta-catenin, Glycogen synthase kinase 3beta (GSK3beta), and Fascin. Gains occurred more frequently than losses (70.5 vs 29.5%). The shortest regions of overlap were gains on chromosomes 8q and 7 followed by 1q, 3q, and 19, supporting the common origin of the different subtypes of SC. The immunohistochemical staining suggests that the sarcomatoid components of SC might have undergone EMT, not triggered by the signaling pathways Notch1, Snail, and TGFbeta1, but probably initiated by an upregulation of c-Jun and a consecutive overexpression of Vimentin and Fascin. The Wnt-pathway was not deregulated because combined membrane and cytoplasmic reactivity for beta-catenin and GSK3beta was observed.

Epithelial-to-mesenchymal transition confers resistance to apoptosis in three murine mammary epithelial cell lines

Epithelial-to-mesenchymal transition (EMT) is an essential embryogenic and developmental process, characterized by altered cellular morphology, loss of cell adhesion, and gain of migratory ability. Dysregulation of this process has been implicated in tumorigenesis, mediating the acquisition of migratory and invasive phenotypes by tumor cells. Mammary epithelial cells provide an excellent model in which to study the process, being derived from mammary gland tissue that utilizes EMT to facilitate branching morphogenesis through which the developing gland migrates into and invades the fat pad. Inappropriate EMT has been heavily implicated in the progression of ductal hyperplasia and mammary tumor metastasis. We examined the morphological and molecular changes of three murine mammary epithelial cell lines following EMT induction. EMT was induced in the EpH-4 and NMuMG cell lines by transforming growth factor (TGF)-beta1 but not by ethanol, while the KIM-2 cell line was partially resistant to TGF-beta1 but responded fully to ethanol. The response to EMT-inducing reagent was shown to be critically dependent on the time of treatment, with confluent cells failing to respond. Timelapse photography identified increased motility during wound healing in cells pre-treated with EMT-inducing reagent compared with untreated controls. Furthermore, EMT conferred resistance to UV-induced apoptosis. Our data indicate that evaluation of characteristics other than loss and gain of phenotypic markers may be of benefit when assessing EMT, and contribute to the evidence suggesting that inappropriate EMT facilitates the acquisition of resistance to apoptosis, a key characteristic required for tumor survival.

Cancer morphology, carcinogenesis and genetic instability: a background

Morphological abnormalities of both the nuclei and the cell bodies of tumour cells were described by Müller in the late 1830s. Abnormalities of mitoses and chromosomes in tumour cells were described in the late 1880s. Von Hansemann, in the 1890s, suggested that tumour cells develop from normal cells because of a tendency to mal-distribution and other changes of chromosomes occurring during mitosis. In the first decades of the 20th century, Mendelian genetics and "gene mapping" of chromosomes were established, and the dominant or recessive bases of the familial predispositions to certain tumour types were recognised. In the same period, the carcinogenic effects of ionising radiations, of certain chemicals and of particular viruses were described. A well-developed "somatic gene-mutational theory" of tumours was postulated by Bauer in 1928. In support of this, in the next three decades, many environmental agents were found to cause mitotic and chromosomal abnormalities in normal cells as well as mutations in germ-line cells of experimental animals. Nevertheless, mitotic, chromosomal, and other mutational theories were not popular explanations of tumour pathogenesis in the first half of the 20th century. Only in the 1960s did somatic mutational mechanisms come to dominate theories of tumour formation, especially as a result of the discoveries of the reactivity of carcinogens with DNA, and that the mutation responsible for xeroderma pigmentosum causes loss of function of a gene involved in the repair of DNA after damage by ultraviolet light (Cleaver in 1968). To explain the complexity of tumourous phenomena, "multi-hit" models gained popularity over "single-hit" models of somatic mutation, and "epigenetic" mechanisms of gene regulation began to be studied in tumour cells. More recently, the documentation of much larger-than-expected numbers of genomic events in tumour cells (by Stoler and co-workers, in 1999) has raised the issue of somatic genetic instability in tumour cells, a field which was pioneered in the 1970s mainly by Loeb. Here these discoveries are traced, beginning with "nuclear instability" though mitotic-and-chromosomal theories, single somatic mutation theories, "multi-hit" somatic theories, "somatic, non-chromosomal, genetic instability" and epigenetic mechanisms in tumour cells as a background to the chapters which follow.

Cripto as a target for cancer immunotherapy

One of the recent, significant advances in cancer immunotherapy is the identification of molecules as targets which regulate cell growth by induction of proliferation and survival signalling pathways. Among them, epidermal growth factor receptor and Her2 have been effectively targeted by monoclonal antibodies. Currently, the treatment of cancer has limitations and most cancer deaths result from the local invasion and distant metastasis of tumour cells. An important insight for the understanding of tumour invasion and metastasis came from the recent discovery that the phenotypic changes of increased motility and invasiveness of cancer cells are reminiscent of the epithelial-mesenchymal transition (EMT) that occurs during embryonic development. The human Cripto, a member of the epidermal growth factor-Cripto, Frl1, and Cryptic (EGF-CFC) protein family and a signalling protein during early embryonic development, plays an important role in cancers. Cripto is attached to the cell membrane through a glycosyl-phosphatidylinositol motif, and is upregulated in a wide range of epithelial cancers. In this paper the authors review the role of Cripto expression in tumourigenesis and in EMT to promote tumour invasion, with emphasis that the unique EGF-like region of Cripto plays a critical role in Cripto signalling-mediated tumour growth and EMT. Therefore, the region should be regarded as a therapeutic point for interruption of the oncogenic and metastatic potential of Cripto for cancer immunotherapy.

Sarcomatoid salivary duct carcinoma

The so-called sarcomatoid salivary duct carcinoma (SSDC) is one of the variants of salivary duct carcinoma (SDC). This neoplasm is characterized by the presence of both a carcinomatous and a sarcomatoid tumor component. The histology and nomenclature of such neoplasms has been a matter of debate for many years. The histologic, immunohistochemical, and electron microscopic findings including those of 4 previously described cases of SSDC are defined and the different attitudes concerning their etiology will be discussed. In addition, the fine-needle aspiration biopsy of such a case is presented for the first time. In analogy to typical SDC there seems to be a predilection for elderly men and a location in major salivary glands. The resected SSDC tumors measured between 1.5 and 3.5 cm. Histologically, each case was a composite of SDC and sarcomatoid carcinoma. Immunohistochemical positivity for epithelial membrane antigen (EMA) and cytokeratins (AE1/AE3, CAM 5.2) was shown in the sarcomatoid tumor component. The important cytomorphologic feature of SSDC is the presence of cohesive clusters and flat sheets of cells with a cribriform pattern, in combination with an atypical spindle cell component. The use of the term SSDC seems more appropriate than the term carcinosarcoma , as the immunohistochemical, electron microscopic, and recent molecular findings in this and other biphasic neoplasms imply a monoclonal origin.

Embryonic reversions and lineage infidelities in tumour cells: genome-based models and role of genetic instability

Reversions to "embryonic precursor"-type cells and infidelities of tumour cell lineage (including metaplasias) have been recognized as aspects of various tumour types since the 19th century. Since then, evidence of these phenomena has been obtained from numerous clinical, biochemical, immunological and molecular biological studies. In particular, microarray studies have suggested that "aberrant" expressions of relevant genes are common. An unexplained aspect of the results of these studies is that, in many tumour types, the embryonic reversion or lineage infidelity only occurs in a proportion of cases. As a parallel development during the molecular biological investigation of tumours over the last several decades, genetic instability has been found much more marked, at least in some preparations of tumour cells, than that identified by means of previous karyotypic investigations of tumours. This study reviews examples of embryonic reversion and lineage infidelity phenomena, which have derived from the various lines of investigation of cancer over the last 150 or so years. Four categories of circumstances of the occurrence of embryonic reversions or lineage infidelities have been identified - (i) as part of the defining phenotype of the tumour, and hence being presumably integral to the tumour type, (ii) present ab initio in only some cases of the tumour type, and presumably being regularly associated with, but incidental to, the essential features of the tumour type, (iii) occurring later in the course of the disease and thus being possibly a manifestation of in vivo genetic instability and "tumour progression" and (iv) arising probably by genetic instability, during the processes, especially cell culture, associated with ex vivo investigations. Genomic models are described which might account for the origin of these phenomena in each of these circumstances.

Gliosarcoma with epithelial differentiation: immunohistochemical and molecular characterization. A case report and review of the literature

Few reported cases of gliosarcomas or glioblastomas with epithelial-like areas exist. Most cases were originally diagnosed as metastatic carcinoma. Focal expression of glial fibrillary acidic protein has helped characterize these tumors as having a glial origin. We report a case of gliosarcoma with multifocal, extensive areas of well-differentiated carcinoma; demonstrating squamous and glandular differentiation. The expression of glial fibrillary acidic protein and epithelial phenotype were mutually exclusive. We performed extensive immunohistochemical analyses and comparative genotypic analysis using microdissection to secure representative glial and epithelial components. Loss of heterozygosity was analyzed with a panel of 12 polymorphic microsatellite markers designed to indicate allelic loss and situated in proximity to known tumor suppressor genes located on chromosomes 1p, 9p, 10q, 17p and 19q. We found comparable patterns of acquired allelic loss between the glial and carcinomatous components, strongly supporting the monoclonal origin of this neoplasm. This case represents an extreme form of phenotypic divergence in a malignant glioma, and constitutes a difficult diagnostic challenge. This heterogeneity reflects the potential for a range of phenotypic expression in malignant gliomas that needs to be recognized. We suggest microdissection genotyping as a molecular technique to better characterize these tumors.

Sarcomatoid salivary duct carcinoma of the oral cavity

This report recounts a new case of sarcomatoid variant of salivary duct carcinoma in a 45-year-old woman. The 1.5-cm polypoid mass protruded from the retromolar area and focally extended into the pharyngeal wall. The patient was free of disease for 11 years. The tumor showed a biphasic malignancy; nondescript sarcomatous proliferation predominated over ductal carcinoma population, with perceptible blending of the two components. The sarcomatoid areas had no heterologous properties. Discohesive pleomorphic cells were immunopositive for vimentin, epithelial membrane antigen and AE1/AE3 at a significant rate. A dual expression of AE1/AE3 and vimentin was also evident in enmeshed foci of conventional cribriform adenocarcinoma. Thus, the sarcomatoid histology represents a dedifferentiated phenotype of salivary duct carcinoma.

Epithelial-mesenchymal transition and its implications for fibrosis

Epithelial to mesenchymal transition (EMT) is a central mechanism for diversifying the cells found in complex tissues. This dynamic process helps organize the formation of the body plan, and while EMT is well studied in the context of embryonic development, it also plays a role in the genesis of fibroblasts during organ fibrosis in adult tissues. Emerging evidence from studies of renal fibrosis suggests that more than a third of all disease-related fibroblasts originate from tubular epithelia at the site of injury. This review highlights recent advances in the process of EMT signaling in health and disease and how it may be attenuated or reversed by selective cytokines and growth factors.

Epithelial-mesenchymal transition and its implications for fibrosis

Epithelial to mesenchymal transition (EMT) is a central mechanism for diversifying the cells found in complex tissues. This dynamic process helps organize the formation of the body plan, and while EMT is well studied in the context of embryonic development, it also plays a role in the genesis of fibroblasts during organ fibrosis in adult tissues. Emerging evidence from studies of renal fibrosis suggests that more than a third of all disease-related fibroblasts originate from tubular epithelia at the site of injury. This review highlights recent advances in the process of EMT signaling in health and disease and how it may be attenuated or reversed by selective cytokines and growth factors.

Sarcomatoid renal cell carcinoma with osteogenic differentiation and paraneoplastic hepatopathy in a dog, possibly related to human Stauffer's syndrome

Sarcomatoid renal cell carcinoma is an uncommon tumour in human beings, and osteogenic differentiation is a rare feature. This report describes such a case in a male dog aged 8 years. The tumour, which showed extensive osseous metaplasia and a few necrotic areas, protruded into the renal pelvis, disrupting the renal capsule. Light microscopical and immunohistochemical examination revealed the epithelial nature of the tumour. Abnormal liver biochemistry, mild hepatocyte degeneration and the absence of histological evidence of metastasis suggested a paraneoplastic hepatopathy.

Epithelial-type and neural-type cadherin expression in malignant noncarcinomatous neoplasms with epithelioid features that involve the soft tissues

CONTEXT

Transmembrane adhesion molecules, epithelial-type cadherin (ECAD) and neural-type cadherin (NCAD), help in regulating transformations between epithelial and mesenchymal cells in the developing embryo and in maintaining the epithelioid phenotype. Consequently, the presence of epithelioid cells in certain malignant noncarcinomatous neoplasms raises speculation that the expression of ECAD and NCAD in these neoplasms may have diagnostic significance.

OBJECTIVE

To investigate the utility of ECAD and NCAD immunoexpression in distinguishing malignant (noncarcinomatous) neoplasms with epithelioid features that involve the soft tissues.

DESIGN

Membranous immunoreactivity of anti-ECAD and anti-NCAD was evaluated on archived cases selected from the files of the Armed Forces Institute of Pathology.

RESULTS

Epithelial-type cadherin was found in biphasic synovial sarcoma (35 of 35 cases), malignant melanoma (13/21), monophasic fibrous synovial sarcoma (13/26), clear cell sarcoma (4/9), poorly differentiated synovial sarcoma (3/13), diffuse mesothelioma (4/20), malignant epithelioid peripheral nerve sheath tumor (1/6), and epithelioid sarcoma (5/62). Neural-type cadherin was observed in chordoma (11/11), biphasic synovial sarcoma (30/35), diffuse mesothelioma (14/20), malignant melanoma (14/25), epithelioid sarcoma (24/63), epithelioid angiosarcoma (1/4), poorly differentiated synovial sarcoma (2/13), clear cell sarcoma (1/10), and monophasic fibrous synovial sarcoma (1/26). Eighteen cases of primary cutaneous squamous cell carcinomas all tested positive for ECAD, whereas NCAD was focally observed in 5 cases. No expression of either molecule was observed in cases of epithelioid hemangioendothelioma (n = 9), alveolar soft part sarcoma (n = 8), and extraskeletal myxoid chondrosarcoma (n = 7).

CONCLUSIONS

Epithelial-type and neural-type cadherins are found in a variety of noncarcinomatous neoplasms with epithelioid features that involve the soft tissues and can be utilized, in association with other immunomarkers, in distinguishing chordoma (100% NCAD) from extraskeletal myxoid chondrosarcoma and conventional chondrosarcoma of bone (0% NCAD), squamous cell carcinoma (100% ECAD) from epithelioid sarcoma (8% ECAD), and biphasic synovial sarcoma (100% ECAD) from diffuse mesothelioma (20% ECAD).

Spindle cell (sarcomatoid) carcinomas of the larynx: a clinicopathologic study of 187 cases

Laryngeal spindle cell (sarcomatoid) carcinomas are uncommon tumors, frequently misdiagnosed as reactive lesions or mesenchymal malignancies. The records of 187 patients with tumors diagnosed as laryngeal spindle cell (sarcomatoid) carcinoma were retrieved from the files of the Otorhinolaryngic Tumor Registry of the Armed Forces Institute of Pathology. There were 174 men and 13 women, 35-92 years of age (average, 65.6 years). Nearly all patients experienced hoarseness (n = 165 [88%] patients) for a mean duration of 11.0 months. Patients admitted to smoking (n = 162 [87%] patients) and/or alcohol use (n = 90 [48%] patients). Most tumors were glottic (n = 132 [71%]), T1 (n = 111 [59%]), 1 and polypoid (n = 185 [99%]), with a mean tumor size of 1.8 cm. Histologically, squamous cell carcinoma (n = 157 [84%]) was noted, ulcerated, and blended with the spindle cell component, which was most frequently arranged in a storiform pattern (n = 92 [49%] tumors). Foci of benign or malignant cartilage and/or bone (n = 13 [7%]) were noted in the spindle cell component. All patients were treated with surgery (n = 90 [48%] patients) or surgery with radiation (n = 97 [52%] patients). Recurrences developed in 85 (45%) patients. Overall, T1 glottic tumors managed by complete surgical eradication had the best outcome (mean follow-up, 7.8 years).

Spindle cell squamous carcinoma of the oesophagus: an analysis of 17 cases, with new immunohistochemical evidence for a clonal origin

AIMS

To study the morphological and immunohistochemical characteristics of spindle cell squamous carcinoma of the oesophagus, in order better to understand the histogenesis of this tumour.

METHODS AND RESULTS

In this study we analysed the morphological and immunohistochemical characteristics of 17 cases of spindle cell squamous carcinoma of the oesophagus. Most tumours were polypoid, but tumours with an ulcerated and infiltrative pattern were also observed. Histologically, most tumours were of superficial type, with a characteristic morphological aspect consisting of two types of tumour cells, i.e. differentiated squamous cells, and spindle cells with transition zones between the two components. On immunohistochemistry, the squamous cells were positive for cytokeratin and the spindle cells showed variable expression of cytokeratin, vimentin and smooth muscle actin. p53 protein was over-expressed in 10 cases, both tumour cell types showing strong nuclear positivity. In most tumours, E-cadherin was expressed in the squamous cells and absent in the spindle cells.

CONCLUSIONS

The similar pattern of p53 protein expression in the two tumour cell types of spindle cell squamous carcinoma of the oesophagus suggests their common origin. The change in adhesion molecule expression with loss of E-cadherin expression may be associated with the acquisition of spindle cell morphology by the squamous tumour cells.

Conditional abatement of tissue fibrosis using nucleoside analogs to selectively corrupt DNA replication in transgenic fibroblasts

Progressive tissue fibrosis can compromise epithelial function resulting in organ failure. Appreciating evidence suggests that fibroblasts provide fibrogenic collagens during such injury. We further tested this notion by attempting to reduce the physiologic consequences of organ fibrosis through the selective killing of fibroblasts at sites of injury. Here, we report the conditional reduction of tissue fibroblasts using the coding sequence for herpesvirus thymidine kinase (DeltaTK) put under the control of a cell-specific promoter from the gene encoding fibroblast-specific protein 1 (FSP1). Transgenic fibroblasts from mice carrying FSP1.DeltaTK minigenes expressed thymidine kinase concordantly with native FSP1 and, compared to transgenic epithelium, were selectively susceptible to the lethal effects of nucleoside analogs either in culture or during experimental renal fibrosis. The numbers of fibroblasts in fibrogenic kidney tissue were reduced on exposure to nucleoside analogs as was the degree of type I collagen deposition and the extent of fibrosis. Fibroblast reduction following the stress of DNA chain termination highlights the important contribution of cell division during fibrogenesis. Our findings convey a proof of principle regarding the importance of FSP1(+) fibroblasts in fibrosis as well as providing a new approach to treating the relentless scarification of tissue.